SEASONING AND IMPREGNATION OF TIMBER 27!) 



to have invariably failed, as indeed have all the salts of 

 metals. The North Eastern Kailway Company always 

 paint the kyanized timberwork to prevent the salts being 

 washed out. This process is a good deal used on the 

 Continent for small timbers such as posts, stakes for grape 

 vines, etc., but as the corrosive is very poisonous care has 

 to be taken in the handling. Timber preserved by this 

 process has a life of seventeen years in Germany. 



Powellized Wood was the treatment of wood by a strong 

 solution of sugar, invented in Great Britain a few years 

 ago. 



Salt is an excellent preservative for timber, and in the 

 days of the old wooden ships a layer of salt between the 

 inner and outer planking secured a year's longer classing 

 at Lloyd's ; it is recommended by the American Lloyd's 

 and still required by the Lake underwriters for new first- 

 class vessels. 



Creosoting, which is the system of timber preservation 

 best known and mostly used in Great Britain, was the 

 invention of Mr. John Bethell in 1838, the same year 

 which saw the invention of burnettizing, and these two 

 may be said to be the only systems which are still largely 

 used. 



Creosoting is by far the best preservative for timber. It is 

 good in all situations and in all conditions, and "even those 

 who largely use the zinc chloride and other processes are 

 unanimous in giving the first place to Creosoting, and are 

 only deterred from using it because of its much greater 

 cost, or because it is unsuitable for the situation where the 

 timber is to be used, such as interior work. 



By this process distilled coal tar is injected under 

 pressure into timber (properly seasoned to allow the 



